Distillation of metals



18, 1934- F. JOHANNSEN 1,985,171

DI STILLATION 0F METALS Filed Jan. 24, 19:53 3 Sheets-Sheet 2 Fig q- 1 21 s 9 s g 21 (HHHHHHHH I1 I] 6 1o 3 \IJ'T 14 Al x I f 1 b u :5

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Dec. 18, 1934. F. JOHANNSEN 1,985,171

I DISTILLATION OF METALS Filed Jan. 24. 1935 3 Sheets-Sheet 3 Patented Dec. 18, 1934- 1,985,171 DISTILLATION O F METALS Friedrich Johannsen, Magdeburg, Germany, asslgnor to firm Fried. Krupp Grusonwerk Aktiengesellschaft, Magdcbnrg-Buckau, Germany Application J 4 In 15 Claims.

Thepresent invention relates to the distillation of metals from their ores or the like, and is especially applicable to zinc or similar metals.

The object of the invention is to provide a 5 process and apparatus wherein the heating of a muflle located within a rotary furnace and containing the materials to be reduced is effected entirely or for the greater part by solid fuel fed at one or more points into the heating-spaces surrounding the muille, wherein upon rotation ofthe furnace, it travels along at a comparatlvely slow rate and is gradually burnt. It is to be understood that, in the following description and claims, in using the term solid fuel, it is intended to exclude powdered coal or the like adapted to be blown into the furnace; in the present process the solid fuel is passed through the furnace at a slow rate owing to the slight inclination of the latter or to the pressure exerted by the feeding in of fresh fuel. This method of heating results in a very considerable prolongation or extension of the heating zone over a considerable length of the furnace thus obtaining a long distilling zone in the muflles without any local overheating. For carrying out the process, fuels containing gas are especially suitable such for example as pit coal, brown. coal briquettes, lignite, slow-combustion and low-temperature coke, etc. It is, generally speaking, sufficient to introduce the fuel at one end of the rotary furnace and to allow it to travel through the muflle along the inclined sole of the furnace either in the same or inverse direction of flow to that of the gases of combustion and also to that taken by the mate- 35 rlal itself. The fuel may, however, be introduced either entirely or partly at other points of the rotary furnace, as for example through one or more openings in the furnace wall.

It is another object of the invention, for the purpose of regulating the process, to provide auxiliary burners for fluid or powdered fuel in addition to the heating by the solid fuel, after the manner described in English Patent Specification It is a further object of the invention, in order to support an extensively protracted combustion, to introduce the combustion air also at various points in the furnace the walls-of the furnace.

advantage may be secured the air either blown or zlesis guided through the inthis way, an extensive use may of materials difficult of co anthracite, etc.

For the ,-as for example through In this case the further at the same time that drawn in through nozlayer of fuel itself and, also be made such as coke,

anuary 24, 1933, Serial No. 653,327 Germany January 25, 1932 (or. zoo-1s fuel used-it is advisable to provide such nozzles in particular at the discharge end of the furnace.

At the same time in the manner already known it is possible, when the air is introduced through nozzles in the walls of the the furnace at which the furnace or at the end of 5 solid fuel is introduced to ensure, by a suitable control of the different air inlets, that air is fed to those nozzles only which are located for the moment below the surface of the layer of fuel.

Yet another object of the invention, to allow of further utilization of the fuel content is to efiect the discharge of the fuel waste directly into a shaft working as a generator in which, by means of blown-in air or air and steam or water, a 'heating gas is generated from the waste, whichgas is guided back into the rotary furnace. Instead of a stationary generator, a generator may be mount-' ed direct in the rotary furnace, for example by widening the last part of the rotary furnace at the discharge end, the residue being gasified in this widened part by the introduction of air,

steam etc.

slag.

The discharge of the waste may be effected at the same time either as a solid or fluid in the distillation of zinc, to give the ore to be treated a great surplus of reduction fuel for the purpose of augmenting the action,

so that the residue of the muflie still contains 50% fuel or more. In order to utilize this fuel for the entire process, it is advisable to return the residue, as heating material, to the heating space after it leaves the muflle. This may be done by hand or by any suitable mechanical means not constituting a feature of the present invention.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be described more fully with reference to the accompanying drawings illustrating 4o exemplifications of furnace installations suitgitudinal section,

Figure 2 represents a able for carrying out this process.

Figure 1 represents the furnace plant in lonportion of the furnace modified by having a generator connected directly to it, Figure 3 represents another modification in which one end of the rotary furnace is constructed as a generator,

Figure 4 representsa Figures 5 and 6 are further modification, sections of Figure 4 showing,

respectively, details of the fuel feeding means and the air inlets.

Figure 7 is a sectional view of a valve fitting which may be inserted in a coil pipe which the residue is discharged, and

Figure 8 is an enlarged sectional view of said coil pipe.

Into the rotary furnace 1 is built a muiile 2 which rotates together with the furnace. The material to be reduced is conducted by means of a worm 3, together with reducing substances, to the inner chamber of the muiiie. The solid fuel serving to heat the muiiie is introduced through the supply pipe 4 into the circular chamber 5 of the rotary furnace surrounding the muffie. The air enters at 6 and passes through the furnace in the direction indicated by the arrow :2; the combustion gases escape at 7. At the point where the air is admitted an auxiliary heating device 8 for the introduction of a fluid or powdered fuel may also be provided if necessary for temperature regulating purposes, although the entire heating may be achieved by the above-described supply of solid fuel. The exhaust gases of combustion pass through the rotary furnace and at the same time heat the muiile 2. The materials travelling in the muiiie in the opposite direction are thus reduced and the zinc etc. evaporated. The vapours escape through the pipe 9 into the condenser 10. The exhaust gases of condensation, containing considerable quantities of carbon monoxide, escape from the condenser through the aperture 11 backwards towards the rotary furnace and pass through it in common with the air introduced at 6. ,In this way the carbon monoxide contained in them is consumed and thus the heating action of the fuel is supported and its consumption reduced. The travelling of the fuel through the rotary furnace in the through direction a: is maintained by a slight inclination of the rotary furance, say to the extent or 2%, so that its progress is sufliciently slow to ensure gradual combustion. As the material consequently travels upwards in the muflie it is at the same -time dammed up therein, so that an effectual filling of the muflie is achieved.

The residues of the'muflle process leave the muiile at 12 and pass into a coil 13 around the muflle, from the opposite end of which coil they are discharged, the end of the coil being for this p rp se bent outwardly as indicated at 14. If necessary valves are inserted in the coil valves to prevent the muiile gases from escaping. Each of such-valves may, for example, be as illustrated in Figure 7 and a valve is inserted at two points; for instance, as depicted in Figure 8, the coil 13 may be cut at the points 28 and 29, at each of which a length of piping is removed to allow of the insertion of a complete valve as illustrated in Figure 7, suitable flanges, as shown in Figure 8, being for this purpose fitted to the coil. Each valve comprises a closure member 30 adapted to be moved into'or out of contact with a cooperating seating 31 by means of a handle 32, the stem 33- connecting the closure member with the handle passing through a gas-tight gland 34. As indicated, the valve seating 31 is mounted in a fitting 35 adapted, as above mentioned, to replace a portion of the coil 13 which has been removed, and provided with a branch 36 in which the gland 34 is located. In use the valves are alternately opened and closed; thus if the valve situated at the point 28 be open and that at the point 29 closed, the residue from the mutlie will, on rotation of the latter, pass throughthe coil as far as the point 28. The valve at this point may then be charged from the opening 14 of the coil and passage of gas is prevented on account of the fact that the valve at the point 28 is closed. Thus, the material having been discharged, the valve at the point 29 is closed and the valve located at 28 opened, and the whole cycle of operations is then repeated.

In the modification illustrated in Figure 2, at the end of the rotary furnace where the fuel waste is removed, a vertical generator 15 is built in, in which in the usual way a gasification of the fuel waste takes place by blowing in air through a mushroom-shaped jet 16 on to the surface of water in a cup 17 from which moisture is picked up. The generator gases pass into the rotary furnace. In this case the gases traverse the furnace in a direction inverse to that shown in Figure 1, draught being induced by such means as a chimney at the other end of the furnace. Consequently, the admission of the air takes place at 18, and at the same place an auxiliary heating means 19 can be provided. Extraction of the ash is effected in the way usual in such generators, namely by hand from the outer edge of the vessel 17.

In the modification illustrated in Figure 3 the fixed head at the lower end is eliminated and the end of the rotary furnace where the fuel waste is withdrawn is so widened as to form a generator 20. The method of operation of this generator is, in all other respects, similar to that according to Figure 2.

The supply of air can be effected, for example, by means of a ring 21 and nozzles 22, preferably in such a manner that the nozzles 22 only come into communication with the interior of the ring 21 when they are at the lower part of their path of movement, that is to say when they are covered by material. In this method of construction an air inlet is, as indicated, provided at both end faces of the widened part. The ash overflows through the opening 18.

Whereas as shown in Figure 1 the solid fuel, which is introduced through the pipe 4, travels slowly in the furnace in the direction of the arrow .1: and is thereby gradually burnt, in the apparatus shown in Figures 4 and 5 fuel is also introduced into the furnace intermediately s in the-direction of the arrow 11, these scoops dip into a trough 25 under I the furnace, which is filled with solid fuel, which is scooped up and when the openings 23 arrive at the top position falls into the furnace. In order to avoid the passage of excessive quantities of gas through the openings 23, a suitable enclosed housing 26 may be placed over the trough 25 and surrounding the furnace. Since, in order to obtain satisfactory heating, coal is chosen as suitable for this supplementary supply .and not coke, it may be found suitable to introduce additional combustion airin the neighbourhood of any or all of the series of openings 23 in. order to burn the hydrocarbons. Such air inlet may take place through nozzles 27.

In the following claims, the term fiuid fuel", wherever it occurs, is to be regarded as inclusive of powdered fuel, as well as fuel which is liquid or gaseous.

What I claim and desire to Patent of the United States is:-

1. A process for the distillation of metals in a mumefittedinarotaryfurnaceaccordingto in part by solid fuel fed into the furnace and burnt while travelling longitudinally within the furnace.

2. A process as in claim 1, according to which the fuel is introduced at one end of the furnace and is consumed during its passage through the furnace, v

3; A process as in claim 1, according to which at least part of the fuel is introduced through openings located intermediately of the length of thefumace.

4. A processfor the distillation of metals in a muiiie fitted in a rotary furnace, according to which the heating of the muflle is effected in part by solid fuel fed into the furnace and burnt while travelling longitudinally within the furnace and in part by means of fluid fuel.

5. A process forthe distillation of metals in a muflie fitted in a rotary furnace, according to which the heating of the mume is effected at least input by solid fuel fed into the furnace and burnt while travelling longitudinally within the furnace and the fuel residue is treated in a generator for the production of combustible gases which are burnt in the furnace.

6. An apparatus for the distillation of metals comprising a substantially horizontally disposed cylinder mounted for rotation about its axis, a cylindrical muile disposed substantially centrally within said cylinder and mounted for rotation therewith, the space between the exterior wall of the muiiie and the interior wall of the cylinder comprising a rotary combustion chamber, means for charging solid fuel and air into said combustion chamber to be burned therein and advanced -1herethrough during combustion to heat said muiiie, means for discharging the products =0f combustion, means for charging, the muiile with material to be distilled, means for discharging the solid residue of distillation while the parts are rotating, and independent means for discharging the distillate.

7. Apparahis as in claimii, wherein said com bustion chamber is provided with an auxiliary opening for admission of fuel located at one end thereof.

8. Apparatusas inclaimo, whereinsaidcylinder is provided with an opening for admission of fuel to said rotary combustion chamber located intermediately of the length thereof.

9. Apparatus as in claim 0, wherein said furnace is provided with anopening at one end and an opening located intermediately of the length of the rotary combustion chamber for the admission of air. a

V 10. 'Apparatusas in claim 6, wherein said furnace is provided with an opening for admission of air located intermediately of the length of said furnace and with means whereby air is admitted only through those openings located for the moment below the surface of the fuel.

11. Apparatus for the distillation of metal comprising in combination a rotary furnace having openings for admission of solid fuel and air to be advanced .therethrough during combustion and for discharge of the products of combustion, at

least one muiile within said furnace and a generator to receive the residue of combustion and having a gas outlet in communication with said furnace.

12. Apparatus as in claim 11, wherein said generator is constituted by an extension of said furnace of a diameter greater than that of said furnace proper.

13. Apparatus as in claim 11, comprising in combination means for injecting air into the residue in said generator.

14. Apparatus for the distillation of metals comprising in combination a rotary furnace having openings for admission of solid fuel and air to be advanced therethrough during combustion and for discharge of the products of combustion, at least one mume within said furnace, means for introducing material to be reduced into said muffle, means for discharging the residue of the distillation process radially of said furnace, a condenser disposed substantially axially of said furnace and means for discharging the distilled metal vapour into said condenser. I

15. Apparatus as in claim 14, comprising, in combination with said radial discharge means, a conduit coiled around said furnace.

FRIEDRICH JOHANNSEN. 

